1. Field of the Invention
The invention concerns a cooling apparatus for a motor vehicle with an internal combustion engine.
2. Description of the Background Art
Cooling apparatuses for motor vehicles are primarily used for cooling an internal combustion engine, but optionally also for cooling a refrigerant circuit for an air conditioner. Consequently, the cooling apparatus generally includes multiple heat exchangers, such as a radiator, an intake air cooler, an oil cooler, and a condenser for cooling the air conditioner's refrigerant. Also associated with the cooling apparatus is a fan, such as an axial fan with a fan shroud. In relatively large motor vehicles, the fan is driven directly by the internal combustion engine through the crankshaft or a belt drive, and hence is mounted in a fixed position relative to the engine. In contrast, the heat exchangers, in particular the radiator, are mounted in a fixed position relative to the vehicle, as is the fan shroud attached to the heat exchanger or heat exchangers. The resulting relative motions between the radiator or fan shroud on the one side and the fan on the other side are compensated by a motion compensating element, also called a compensating element, with the compensating element simultaneously performing a sealing function.
A cooling apparatus of this nature has been disclosed in the applicant's DE 33 04 297 C2, which is incorporated herein by reference. The fan, implemented as an axial fan, has a circumferential ring or baffle ring, which is rigidly attached to the blade tips and rotates with the fan. The upstream, overhanging end of the circumferential ring projects into an intake nozzle which, like the fan, is mounted in a fixed position relative to the engine. Located between a fan shroud, which is attached to a radiator mounted in a fixed position relative to the engine, and the intake nozzle is a motion compensating element in the form of an elastic lip, by means of which relative motions are compensated.
Disclosed in the applicant's DE 10 2007 031 462 A1, which is incorporated herein by reference, is another cooling apparatus for a motor vehicle, wherein a motion compensating element is located between a radiator and a fan shroud, by which means the fan shroud has a flow-optimized contour, which is to say without breaks or sharp bends.
Disclosed in the applicant's DE 10 2006 047 236 A1, which corresponds to U.S. Publication No. 2010/0014967, which is incorporated herein by reference, is an axial fan with a recessed circumferential ring and upstream baffle ring, which in addition to aerodynamic advantages has the advantage of a small axial installation depth, which is especially important in modern vehicles on account of the limited installation space.
Disclosed in EP 0 746 689 B1 is an axial fan driven by an electric motor, known as an electric fan, wherein the axial fan has a circumferential ring attached to the blade tips, and rotates inside a fan frame or a frame ring. Together with the stationary frame ring, the rotating fan ring forms an annular gap, through which passes recirculating air—in the opposite direction to the primary flow in the fan. Located on the frame ring in the vicinity of the annular gap are vanes extending axially and projecting approximately radially inward, which are intended to counteract a twisting of the recirculation flow.